@robert: are you using webpack loader? We tracked this bug to an elm-webpack-loader behaviour. here is the issue. https://github.com/rtfeldman/elm-webpack-loader/issues/60
For now, the workaround I am using is to import Json.Decode in my Ports file. On Monday, 8 August 2016 22:30:16 UTC+5:30, Robert Walter wrote: > > It doesn't seem like it is tracked. I ran into the same(?) issue in my > project and I tried to create a SSCCE so I could file an issue, but the > thing is I cannot get a SSCCE to fail like my project. My projec tis in the > middle of a bigger refactoring, which makes it particularly hard for me to > boil it down to a SSCCE. > > @Aditya: can you share some more information? In my case, my port module > is called "Ports". If I do not have an import statement for Json.Decode, I > run into the very error you mentioned at the beginning. Adding the import > statement fixes the issue. > > > > On Monday, August 1, 2016 at 6:01:09 AM UTC+2, Duane Johnson wrote: >> >> Cool bug find :) Is it tracked on >> https://github.com/elm-lang/elm-compiler/issues ? >> >> On Sun, Jul 31, 2016 at 3:01 AM, Aditya Vishwakarma <[email protected] >> > wrote: >> >>> Hi >>> >>> So I dug deeper into this issue. turns out that the JS code for my port >>> module was being emitted before the JS of Json.Decode module. >>> >>> After some research, I found that if the project's port module has: >>> >>> - Name beginning with a letter before J, and >>> - does not have a declared dependency on Json.Decode >>> >>> Then the elm compiler will emit the port module code before >>> `Json.Decode` which causes all decoders to be `Undefined`. This results in >>> all user defined incoming ports to stop throw exceptions. >>> >>> SSCCE: https://github.com/adityav/elm-ports-issue >>> >>> >>> On Friday, 29 July 2016 02:27:41 UTC+5:30, Aditya Vishwakarma wrote: >>>> >>>> Hi >>>> >>>> I am getting Uncaught TypeError: Cannot read property 'tag' of >>>> undefined in a sample code I built to tryout elm. The error happen when I >>>> send JSON data across the elm port from JS side. >>>> >>>> Port defn: >>>> https://github.com/adityav/elm-reddit-listing/blob/master/src/AppPorts.elm#L14 >>>> JS call which causes this issue: >>>> https://github.com/adityav/elm-reddit-listing/blob/master/src/index.js#L36 >>>> git repo: https://github.com/adityav/elm-reddit-listing >>>> >>>> To run. Simply do >>>> npm install && elm package install >>>> npm start >>>> >>>> and open http://localhost:8080/. A listing of /r/elm should show up >>>> when the app works. >>>> >>>> A screenshot of the exact location where the error occurs: >>>> >>>> >>>> <https://lh3.googleusercontent.com/-5aH4m9n6gEw/V5pu35oQsEI/AAAAAAAAEbw/QKXJrtSqgcA6-Dfe_BVsDOYPpn9BHl6MACLcB/s1600/Screen%2BShot%2B2016-07-29%2Bat%2B1.39.20%2BAM.png> >>>> >>>> People on slack recommended me to remove elm-stuff/build-artifacts and >>>> try again. It didn't work so I removed node_modules and elm-stuff >>>> directories and reinstalled the whole thing. Didn't work as well. >>>> The code was working before I decided to clean it up a little to show >>>> to my teammates. Stopped working the moment I shared the github link with >>>> them. :| >>>> >>>> anyone got any ideas on this? >>>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Elm Discuss" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
